Isolation of two tryptic fragments from bovine beta-lactoglobulin and assessment of their thermal gelation ability

Two tryptic peptides of beta-lactoglobulin (beta-Lg) were isolated and by d ynamic oscillation rheology it was assessed whether they form thermal gels at pH 7.5 in a concentration of 1.2.7 mM, corresponding to a 5% beta-Lg sol ution. The fragments f41-60 and f61-70 disulfide-linked to f149-162 were is olated to more than 80% purity. None of these fragments formed a gel upon h eating to 80 degrees C for 1 h and cooling to 25 degrees C. This suggests t hat these parts of the beta-Lg are not primarily responsible for thermal ge lation at neutral pH, although they may be involved in initial or secondary association of molecules to form building blocks or in stabilizing the fin al gel network.